目的探讨急性砷暴露小鼠机体谷胱甘肽(glutathione,GSH)水平变化及其调控酶γ-谷氨酰半胱氨酸合成酶(γ-glutamylcysteine synthetase,γ-GCS)、谷胱甘肽还原酶(glutathione reductase,GR)和谷胱甘肽转移酶(glutathione transferase,GST)的蛋白表达。方法将170只健康封闭群8周龄清洁级昆明雌性小鼠按体重随机分为5组,分别为对照(蒸馏水)组(10只)和2.5、5、10、20mg/kg亚砷酸钠染毒组(各40只)。采用一次性灌胃方式进行染毒,染毒容量为10ml/kg。染毒后6、12、24、48h(对照组染毒12h),采用二硫双硝基苯甲酸(DTNB)法测定全血中GSH含量;采用Beutler改良法测定肝脏中GSH含量;采用WesternBlot法检测肝脏中γ-GCSm、γ-GCSc、GR和GST的蛋白表达。结果随着亚砷酸钠染毒剂量的升高,小鼠全血GSH含量整体呈上升趋势。随着亚砷酸钠染毒剂量的升高和染毒时间的延长,小鼠肝组织中GSH含量整体呈先上升后下降的趋势;并均在染毒12h时达到最高。亚砷酸钠染毒还能够显著诱导机体GSH相关调控酶(γ-GCSm、γ-GCSc、GR和GST)的蛋白表达;且随着亚砷酸钠染毒剂量的升高和染毒时间的延长,其蛋白表达均逐渐增加。结论急性砷暴露能够有效地持续性诱导肝脏GSH相关调控酶γ-GCS、GR和GST的蛋白表达。
Objective To investigate the levels of glutathione (GSH) and the protein expression of GSH-related regulation enzymes (γ-GCSm,γ-GCSc,GR and GST) in mice after acute arsenic exposure. Methods One hundred and seventy healthy Kunming mice(closed colony, clean class, 8-week-old females) were randomly divided to five groups, control (distilled water) group(10 mice) and 2.5, 5, 10 and 20 mg/kg body weight NaAsO2 exposure groups (40 mice each group). The treatment was conducted through garage, the volume was 10 ml/kg. The administration period for each exposure group were 6, 12, 24 and 48 h (control group was 12 h), then the blood and liver tissue were collected. The concentrations of GSH in blood and liver were determined by dithiobis-nitrobenzoic acid (DTNB) and improved Beutler methods. Western Blot was used to evaluate the protein expression of GSH-related regulation enzymes (γ-GCSm,γ-GCSc, GR and GST) in liver. Results The GSH levels in blood increased with increasing of exposure doses and exposure time. However,the levels of GSH in liver increased at first, then decreased,but all still were higher than control. In the same exposure concentration groups,the concentration of GSH in liver increased from the 6th hour to the 12th hour of the treatment and then decreased,and all higher than control. The protein expressions of γ-GCSm,γ-GCSc, GR and GST were all induced after arsenic exposure,and the protein expressions had a Positive correlation with the NaAsO2 exposure dose and time. Conclusion Acute arsenic exposure may induce a strong and sustained protein expression of GSH-related regulation enzymes (γ-GCSm,γ-GCSc,GR and GST) in the liver.